ASA vpn page loading slow

when you need around 2 minutes to load your vpn portal page, you might need check the setting of following: 

is the network storage accessible?

user-storage

To store personalized user information between clientless SSL VPN sessions, use the user storage command in group-policy webvpn mode. To disable user storage, use the noversionof the command.

user-storage NETFS-location

no user-storage]

Syntax Description

NETFS-location

Specifies a file system desination in the form proto://user:password@host:port/path

of course you can check via ASDM